On Linux, clear the signal mask of the launched inferior
Summary:
Due to fork()/execve(), the launched inferior inherits the signal mask of its parent (lldb-server). But because lldb-server modifies its signal mask (It blocks SIGCHLD, for example), the inferior starts with some signals being initially blocked.
One consequence is that TestCallThatRestarts.ExprCommandThatRestartsTestCase (test/expression_command/call-restarts) fails because sigchld_handler() in lotta-signals.c is not called, due to the SIGCHLD signal being blocked.
To prevent the signal masking done by lldb-server from affecting the created inferior, the signal mask of the inferior is now cleared before the execve().
Patch by: Yacine Belkadi
Reviewers: ovyalov, labath
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D12138
llvm-svn: 245436
diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
index 7203da2..84e020d 100644
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
@@ -554,7 +554,8 @@
eDupStderrFailed,
eChdirFailed,
eExecFailed,
- eSetGidFailed
+ eSetGidFailed,
+ eSetSigMaskFailed
};
// Child process.
@@ -632,6 +633,12 @@
}
}
+ // Clear the signal mask to prevent the child from being affected by
+ // any masking done by the parent.
+ sigset_t set;
+ if (sigemptyset(&set) != 0 || pthread_sigmask(SIG_SETMASK, &set, nullptr) != 0)
+ exit(eSetSigMaskFailed);
+
// Execute. We should never return...
execve(argv[0],
const_cast<char *const *>(argv),
@@ -689,6 +696,9 @@
case eSetGidFailed:
error.SetErrorString("Child setgid failed.");
break;
+ case eSetSigMaskFailed:
+ error.SetErrorString("Child failed to set signal mask.");
+ break;
default:
error.SetErrorString("Child returned unknown exit status.");
break;